3D printing is a technology based on mathematical model files, using adhesive materials, such as special wax, powdered metal or plastic materials, applying a layer-by-layer printing method to construct an object. It is different from a traditional material construction method, and is a new three dimensional layer-by-layer printing method via gradually adding materials. With the rapid development of 3D printing technology, laser technology, due to its speed and accuracy, has been widely applied to 3D printing as the source of energy. Specifically, photosensitive resin stereolithography apparatus (SLA) has dominated the market. SLA uses the principle of three dimensional sculpture, a resin tank is filled with liquid photosensitive resin, and the photosensitive resin is cured after a fast UV laser irradiation to directly obtain a cured resin or similar plastic product.
The design and optimization of the optical system of a laser 3D printer directly affects the printing precision, speed, and stability. In existing optical systems, the laser often reaches the resin tank after multiple reflections. When the laser is reflected, a part of the laser is lost, resulting in reduced laser intensity. Further, multiple reflections raised the requirements for precisely placing the printer parts inside a 3D printer. For example, CN104228068A discloses a rapid SLA 3D printer and a printing method using thereof.
In order to achieve the best focus, a reflection mirror is placed directly underneath the resin tank. 3D printing can be carried out by reflecting the laser via the reflection mirror. In addition, to achieve the best optical path, operators will manually adjust the location of printer parts. It not only is time consuming, but also affects printing quality, not meeting printing precision, speed, and, and product stability requirements. Especially for high-end applications, such as modeling jewelry, dental tooth mold, prototype models, the printing needs cannot be met.